The present invention relates to substituted phenol compounds having antimicrobial activity. These compounds are useful as fragrance or flavor compounds having antimicrobial activity. The present invention further relates to detergent, personal care and other products having antimicrobial activity containing the substituted phenol compounds of the present invention.
Fragrances are commonly incorporated in a wide variety of household, personal care, and industrial items, from perfumes to cleansers, to impart a pleasing odor to the item. Some fragrances have been reported to have weak bacteriostatic activity. However, this activity is believed to be too weak to be of practical use. See J. A. Morris et al., J. Amer. Oil Chem. Soc. 56(5):595-603 (1979).
One way used to achieve sufficient antimicrobial activity of certain fragrances is to increase the effective fragrance ingredient concentration until the desired activity is achieved. For example, U.S. Pat. No. 5,306,707 used 30% effective perfume ingredients to achieve activity in the combination. However, this produces an active perfume having an odor that is not pleasing and is not acceptable to the consumer in a final consumer product. Further, these fragrances also have an unacceptably high odor intensity index as the perfumer tries to mask the odor of the effective material with large amounts of other fragrance ingredients or materials having a high intensity. There is an inverse relationship between the activity of the effective fragrance material and its odor acceptability; that is, as antimicrobial activity increases, odor acceptability decreases.
Certain precursors of the present invention have been shown to have antimicrobial activity. The compounds thymol, carvacrol, cinnamaldehyde and eugenol were tested alone or in combination against oral bacteria. The compounds showed an inhibitory activity on several microorganisms and a synergistic effect was observed with certain combinations. The four compounds can be used alone or in combination, such as eugenol and thymol, eugenol and carvacrol, thymol and carvacrol in the treatment of oral infectious diseases. See N. Didry et al., Pharm. Acta Helv., 69(1):25-8 (1994).
The antimicrobial activity of thymol, carvacrol, and cinnamaldehyde was also tested in several in vitro methods on bacteria involved in upper respiratory tract infections. The broad spectrum activity and synergistic effects observed with some combinations (especially thymol and carvacrol) could allow the use of the 3 compounds alone or in combination for the treatment of respiratory infections. N. Didry et al., Pharmazie, 48(4), 301-4 (1993). Although thymol and carvacrol have antimicrobial activity, use of these compounds is limited as flavors and fragrances due to their becoming hedonically unacceptable above certain concentrations.
Some of the compounds of the present invention have not been previously reported. Others have been reported for use as intermediates in synthesis reactions. These include ortho allyl thymol, ortho propyl thymol, para propyl carvacrol, ortho propyl carvacrol, para propyl thymol, ortho allyl para tert-butyl phenol, and ortho propyl para tert-butyl phenol. See Bu-Hou et al. "Bull. Soc. Chim. Fr.," vol. 5 p. 12 (1954); P. Sen, "J. Indian Chem. Soc.," vol. 30 p. 801 (1953); Rosenmund et al. "Arch. Pharm. (Weinheim Ger.)," vol 408 (1928); P. Sen "J. Indian Chem. Soc.," vol. 30, p. 61 (1953); and Rosenmund et al. "Arch. Pharm. (Weinheim Ger.)" vol. 313 (1927), respectively.
The present invention has also been determined to be suitable for flavor applications. The present invention used in certain combinations can have beneficial taste characteristics such as vanillin-like, spicy or herbal.